🤓 New M.Sc. program: Earth System Dynamics & Evolution 🤓
fau-earth-system-science.github.io starting October 2026! PostDoc positions available
12.03.2026 10:23
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🤓 New M.Sc. program: Earth System Dynamics & Evolution 🤓
fau-earth-system-science.github.io starting October 2026! PostDoc positions available
The rarest of the rare! This holy-grail dream fish is a larval-stage #monkfish, aka #goosefish.
Shot in the wild, using scuba, while diving at night over water several thousand feet deep, several miles offshore from Kumejima, Okinawa.
#larvalfish #blackwater #gug #deepseafish
Yup!
A larval Macrourid sighting at 917 m! ROV pilots filmed future-fish during the #OBVI #LivingBioreactors expedition, supported @schmidtsciences.bsky.social. Scientists are studying midwater organisms and how they sequester carbon.
📢 Including fossil tips in your phylogeny can double your continuous trait model fitting accuracy!
Updated preprint out now on @ecoevorxiv.bsky.social.
🔗 doi.org/10.32942/X27...
with @pedrolgodoy.bsky.social @macroecoevoale.bsky.social and @bethanyjallen.bsky.social
🌿 Postdoc opportunity in plant evolutionary ecology/genetics!
My lab in the Dept. of Ecology & Evolutionary Biology at the University of Michigan is recruiting a postdoctoral researcher to start Fall 2026.
We study plant adaptation, using weeds as model systems.
#Postdoc #EcoEvo
Pls RT!
Jack with an important thread on the uncertainty surrounding the roots of today's major ray-finned fish lineages, how to tackle it, and (most importantly) why it all matters.
A wild creature. Eric Hilton showed me one last year. Really wonder what the skeleton looks like.
Paper here: deepblue.lib.umich.edu/bitstreams/0...
There’s no shortage of Paleozoic fossil fishes (some days I feel like there are too many). But there *is* a lack of good anatomical data that can help us resolve their relationships. It’s a systematically underexplored aspect of vertebrate paleontology and evolution—we need more eyes on the problem.
This last point isn’t isolated. We have similar problems identifying definitive Paleozoic members of the polypterid and neopterygian total groups, even though molecular estimates suggest they should/must be down there. (Watch this space.)
Third, nearly 200 years after Agassiz we *still* haven’t identified clear acipenseriform relatives from pre-Jurassic strata. The usual suspects repeatedly bubble up in these discussions (here’s looking at you, Birgeria and Saurichthys), but this is generally not supported by phylogenetic analyses.
Second, fossils—including those collected long ago and studied many times before—can still yield important new information bearing on how we interpret living species.
First, even today we’re still wrestling with basic homologies in what I’d argue are pretty well-known groups of vertebrates.
Meme featuring panels from Watchmen, depicting Doctor Manhattan on the Moon contemplating time. Speech bubbles indicate that Chondrosteus can tell us something about the origin of sturgeons every time we look at it, written here as “It is 1833/1927/2026. Chondrosteus can tell us about the origin of sturgeons.”
So, what to take away from all of this?
This provides clear paleontological support for a congruent re-interpretation of acipenseriform jaw bone homologies made recently on the basis of comparative studies of facial musculature in living actinopterygians: link.springer.com/article/10.1...
It fails the test of conjunction: two sets of putative dermopalatines occur in the same fish, so cannot be homologues. Instead, we argue that the series of tooth-bearing bones are true dermopalatines, and the strap-like lateral “dermopalatine” looks like a maxilla because . . . it *is* one.
Close up of three CT models of rounded, tooth-bearing bones.
A series of tooth-bearing bones here is not at all unusual: they correspond positionally and anatomically to dermopalatines of other bony fishes. But what about that strap-shaped "dermopalatine" that forms the margin of the mouth?
Inner surface of jaws from previous post. The significant feature is three tooth-bearing plates on ventral margin of the palate.
But flip the jaws around and look at the inside, and you see something entirely new. A series of three tooth-bearing bones lies in front of the ectopterygoid and along the ventral margin of the entopterygoid.
Upper jaw of Chondrosteus, based on CT data. Models rendered in shades of gray and blue. A strap-like bone identified as the dermopalatine forms the ventrolateral margin of the jaw. The palate extends above it. A googly eye marks the approximate position of the orbit. It looks a bit like an angry muppet.
Information from CT helps corroborate many aspects of past work but provided some key new insights on upper jaw structure. Here’s the upper jaw shown in lateral view, with the strap-like “dermopalatine” that looks suspiciously like a maxilla at the bottom (googly eye to help with orientation).
Photo of Willy Bemis, Colin Patterson, Lance Grande, and Pete Forey posed behind a framed specimen of Chondrosteus. From: https://deepblue.lib.umich.edu/bitstreams/c2ded20a-21e2-43ba-82cf-c26e588cc685/download
A set of smiling paleontologists (participants in Grande symposium at NAPC 2024), with Lance Grande in the front row, posing on stone steps with columns behind. From: https://deepblue.lib.umich.edu/bitstreams/c2ded20a-21e2-43ba-82cf-c26e588cc685/download
Like so many projects, it ended up on a back burner. But in 2024 I helped organize NAPC in Ann Arbor, which included a symposium honoring Lance Grande. Given Lance's contributions to our understanding of acipenseriforms (and other fishes), Chondrosteus seemed like a good choice for the Festschrift.
Multicolored image showing a CT model of a fish skull. Different anatomical regions appear as contrasting colors, and individual bones are labeled.
We were struck by how closely the large lateral upper jaw bone—identified as a dermopalatine in living acipenseriforms—resembled the maxilla of early ray-finned fishes. So I borrowed the specimen and zapped it with the new (at the time) CT scanner at Michigan in late 2017. Beautiful scan data.
Image of a photogrammetric model of the fossil skull of Chondrosteus set against a dark blue background.
It’s now the mid-2010s. Sam Giles and I are digging through the fossil fish collection at NHM London and come across this specimen of Chondrosteus. Unlike most, it’s laterally rather than dorsoventrally compressed. And its jaws look oddly . . . normal? umorf.ummp.lsa.umich.edu/wp/specimen-...
And, as is so often the case, the devil is in the details.
Although Chondrosteus was redescribed as recently as 2009, the limitations of existing material—much of it collected during the 1800s and prepared to the standard of the time—meant finer details were elusive. www.tandfonline.com/doi/abs/10.1...
Line-drawing reconstruction of Chondrosteus that makes it look more-or-less like a modern sturgeon. From Woodward's "Catalogue of Fossil Fishes in the British Museum (Natural History)".
By the end of the 19th century, Chondrosteus was widely accepted as an early relative of sturgeons. Some sturgeon-like features (a long snout) were even projected onto it, as in this reconstruction by Arthur Smith Woodward (of later Piltdown fame) that would reappear in generations of textbooks.
Lithograph of a Chondrosteus fossil showing well-ossified skull and fins but practically no other bony skeleton in between. From Egerton (1858) https://www.jstor.org/stable/pdf/108682.pdf
Fast forward to the 1850s and Chondrosteus acipenseroides is formally named and described by Egerton based on substantially more complete material than that available to Agassiz. The resemblance to today's acipenseriforms is unmistakable.
Today, that specimen examined by Agassiz resides—along with other parts of the Philpot collection—in the Oxford University Museum of Natural History. oumnh.ox.ac.uk/collections-...
Text from “Recherches sur les Poissons Fossiles” in French, reporting a fossil Acipenser from the Eocene London Clay, and a substantially older fossil from the Jurassic of Lyme Regis named Chondrosteus acipenseroides.
Among the fossils in the Philpot collection was a tail that bore a striking similarity to that of living sturgeons. Agassiz called this Chondrosteus acipenseroides (as a name only) and recognized it as the earliest example of a sturgeon-like fish.
Text from “Recherches sur les Poissons Fossiles” in French, describing Agassiz’s visit to the collection of Elizabeth Philpot and his interactions with both her and Mary Anning.
Louis Agassiz, a mentee of Georges Cuvier, was touring Europe studying fossil fishes at this time. Lyme Regis was an essential stop. Agassiz writes of Mary Anning's discoveries, the extensive collection assembled by Elizabeth Philpot, and his interactions with these pioneering paleontologists.
